Gage protector



Jan. 12, 1960 R A CQQPER GAGE PROTECTOR Filed Aug. 15, 1958 INVENTOR.

ATTOR/VE United States Patent GAGE PROTECTOR Richard A. Cooper, Hawthorne, Calif. Application August 15, 1958, Serial No. 755,272

4 Claims. (Cl. 137-50513) This invention relates to pressure-responsive protective devices, and more particularly to an automatically operating valve device for protecting a gage or similar pressure indicator against damage due to pressure overload.

A main object of the invention is to provide a novel and improved gage protector which is simple in construction, which is easy to install, and which operates in a reliable and dependable manner to cut off a pressure gauge or similar indicator from its associated source of fluid pressure when the fluid pressure rises above a predetermined maximum value, which may correspond to the maximum pressure value for which the gage is designed.

A further object of the invention is to provide an improved gage protector which is inexpensive to manufacture, which is durable in construction, and which may be adjusted to preset the maximum value of fluid pressure at which it operates, whereby the protector may be employed with different pressure gages having various maximum pressure-indication values.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

Figure 1 is a longitudinal vertical cross sectional view taken through a gage protector constructed in accordance with the present invention, shown in normal, open position.

Figure 2 is a longitudinal vertical cross sectional view, similar to Figure 1, but showing the gage protector in its closed position responsive to fluid pressure exceeding the range of the associated pressure gage.

Figure 3 is a transverse vertical cross sectional view taken on the line 33 of Figure 2.

Figure 4 is a fragmentary transverse vertical cross sectional view taken on the line 4-4 of Figure 2.

Figure 5 is a fragmentary transverse vertical cross sectional view taken on the line 55 of Figure 2.

Referring to the drawings, 11 generally designates an improved gage protector according to this invention. The gage protector comprises a generally rectangular housing 12 which is formed with a cylindrical cavity 13 opening at one end of the housing and which is provided at its open end with internal threads 14 with which is engaged a closure plug 15. The closure plug 15 has a cylindrical body portion 16 which is received in a correspondingly shaped enlarged cylindrical portion of the housing cavity,

and the closure plug is further formed with an annular grove 17 in which is mounted an annular resilient-deformable sealing ring 18 which makes sealing contact with the surface of the cylindrical bore receiving the smooth portion 16 of the plug 15.

The cavity 13 defines a wall portion 19 at the end of housing 12 opposite plug 15. The wall portion 19 is formed with an inlet passage 20 to which is connected the conduit 21 leading from the source of fluid pressure to be measured. Opposite passage 20, the wall portion 19 is formed with an outlet passage 22 to which is connected a conduit 23 leading to the pressure gauge em 2,920,646 Patented Jan; 12, 1960 axis of the cavity than is the port 25, as is clearly shown in Figures 1 and 2.

Designated at 27 is an axially movable valve element which is slidably mounted in the control cavity 13 and which is formed with the end flanges 28 and 29 making sliding contact with the inside surface of the cylindrical cavity 13, but being formed with flattened portions 30 to define clearance between the valve member 27 and the interior wall surface of said cavity, and to allow free flow of fluid past the valve element.

The valve element 27 is formed at the flange 29- with an annular groove 32 facing the surface 24 and having a radius relative to the axis of the cavity 13 which is intermediate the radial distances of the ports 25 and 26 from said axis. Seated in the annular groove 32 is an annular sealing ring 33 of deformable resilient material adapted to at times engage the surface 24 and to seal off port 25 from port 26, since the port 26 will then be included inside the sealing ring 33.

Valve member 27 is formed with the axial cylindrical internal cavity 34 opening at the side thereof facing the surface 24. Designated at 35 is a flexible bellows memher having one end thereof sealingly secured to the end wall 37 of the valve member 27. The opposite end of the bellows member 35 is sealingly secured to an annular collar member 38 which is slidably and sealingly engaged on a piston member 39 which is in turn slidably received in a sleeve member 40 formed integrally with the collar member 38 and sealingly engaged in a bore 41 formed in the wall portion 19 in axial alignment with the cylindrical cavity 13.

Wall portion 19 is formed on its outer side with an axial recess 45, and a fastening nut 46 is threadedly engaged on the sleeve member 40 in said recess 45. A closure plug 47 is threadedly engaged in the outer portion of recess 45, as shown, said plug being provided with a transverse tool-engaging groove 48, whereby the plug may be removed whenever necessary. The plug 47 is provided withan annular groove in its peripheral surface which receives a resilient deformable sealing ring 49, sealing the plug in the recess 45.

The inner end portion of piston member 39 is formed with an annular flange 50 against which bears one end of a coiled spring 51, the opposite end of said coil spring bearing against the wall 37 of valve member 27, biasing said valve member against the closure plug 15, as shown in Figure 1. The biasing force of spring 51 is adjusted by an adjusting plug element 52 which is threadedly engaged in the sleeve member 40 and which is accessible for adjustment by the removal of the cover plug 47 from the recess 45. As shown in Figure l, the adjusting plug 52 bears against the end of the piston member 39, whereby the position of said piston member may be adjusted axially to vary the biasing force of the coil spring 51.

Under normal conditions, fluid from the source enters the passage 20 and passes through port 25 and cavity 13 to the port 26, and thence to the pressure gage through the conduit 23. When the fluid pressure is below the maximum value of the associated pressure gage or other indicator, the force of spring 51 is suflicient to keep the bellows 35 extended and maintain the valve member 27 substantially in the position of Figure 1, wherein communication exists between ports 25 and 26. However, when the fluid pressure exceeds the maximum value specified for the pressure gage or other fluid pressure indicator, the pressure in the cavity 13 overcomes the biasing force of spring 51 and moves the valveelement 27 toward the left toward the position shown in Figure 2. This causes the sealing ring 33 to sealingly engage against surface 24 and blocks communication between ports 25 and 26, preventing further admission of fluid to the pressure gage or other pressure indicator. When the pressure drops below the specified maximum value, the spring 51 moves the valve member 27 to the right, as viewed in Figure 2, disengaging the sealing ring 33 from the surface 24 and again establishing communication between ports 25 and 26.

As will be readily apparent, the gage or other pressure indicator is thus protected against damage from excessive pressure and is allowed to operate normally as long as the pressure is below the maximum value which it is intended to indicate.

The cut off pressure may be readily adjusted by adjusting the plug member 52, as above described, whereby the biasing force of the coil spring 51 is accordingly adjusted.

While a specific embodiment of an improved gage protector has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those'skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. A gage protector comprising a housing having a wall provided with an inlet passage adapted to be connected to a source of pressure fluid and an outlet passage adapted to be connected to a pressure gage, a controlcavity in said housing adjacent said wall, said wall being formed with an inlet port connecting said inlet passage to said control cavity at all times and an outlet port normally connecting said control cavity to said outlet passage, a movable valve element mounted in said control cavity and having sealing means constructed and arranged to engage said wall and isolate said outlet port from the control cavity responsive to movement or" said valve element into engagement with said wall, a yieldable chamber connecting said valve element to said wall and being sealed with respect to said control cavity, and spring means in said chamber bearing between said wall and said valve element and biasing said valve element away from said wall, the pressure in the control cavity acting against the valve element in opposition to said spring means, whereby said sealing means will engage said wall to isolate said outlet port from the control cavity when suflicient pressure exists in said cavity to overcome said spring means.

2. A gage protector comprising a housing having a wall provided with an inlet passage adapted to be connected to a source of pressure fluid and an outlet passage adapted to be connected to a pressure gage, a control cavity formed in said housing adjacent said wall, said wall being formed with an inlet port connecting said inlet passage to said control cavity at all times and an outlet port normally connecting said control cavity to said outlet passage, a movable valve element mounted in said control cavity and having sealing means constructed and arranged to engage said wall and isolate said outlet port from the control cavity responsive to movement of said valve element into engagement with said wall, a. bellows member mounted coaxially with said valve element and connecting said valve element to said wall and being sealed with respect to said control cavity, and spring means in said bellows member bearing between said wall and said valve element and biasing said valve element away from said wall, the pressure in the control cavity acting against the valve element 'in opposition to said spring means, whereby said-sealing means will engage said wall to isolate said outlet port from the control cavity when suificient pressure exists in said cavity to overcome said spring means.

3. A gage protector comprising a housing having a wall provided with an inlet passage adapted to be connected to a source of pressure fluid and an outlet passage adapted to be connected to a pressure gage, a control cavity formed in said housing adjacent said wall, said wall being formed with an inlet port connecting said inlet passage to said control cavity at all times and an outlet port normally connecting said control cavity to said outlet passage, a movable valve element mounted in said control cavity, an annular resilient deformable sealing ring mounted on said valve member in a position to engage said wall around the outlet port and isolate said outlet port from the control cavity responsive to movement of said valve element into engagement with said wall, a bellows member mounted coaxially with said valve element and connecting said valve element to said wall and being sealed with respect to said control cavity, and spring means in said bellows member bearing between said wall and said valve element biasing said valve element away from said wall, the pressure in the control cavity acting against the valve element in opposition to said spring means, whereby said sealing means will engage said .wall to isolate said outlet port from the control cavity when suificient pressure exists in said cavity to overcome said spring means.

4. A gage protector comprising a housing having a wall provided with an inlet passage adapted to be connected to a source of pressure fluid and an outlet passage adapted to be connected to a pressure gage, said housing being formed adjacent said wall with a control cavity, said wall being formed with an outlet port connecting said control cavity to said outlet passage and an inlet port connecting said control cavity to said inlet passage, said inlet port being spaced a substantially greater distance from the center of said wall than said outlet port, a movable valve element slidably mounted in said control cavity for movement along an axis including the center of said wall and having a substantially annular sealing element mounted thereon and being engageable with said wall, the sealing element being located so as to isolate the outlet port from the control cavity when it engages said wall responsive to movement of the valve element toward said wall, a yieldable chamber connecting said valve element to said wall and being sealed with respect to said control cavity, and spring means in said chamber bearing between said wall and said valve element and biasing said valve element away from said wall, the pressure in the control cavity acting against the valve element in opposition to said spring means, whereby said sealing element will engage said wall and isolate said outlet port from the control cavity when suflicient pressure exists in said cavity to overcome said spring means.

No references cited. 

